Coupling of halogenated organic compounds



3,046,304 Patented July 24, 1962 ice 3,046,304 CGUPLING F HALOGENATED ORGANIC CUR [POUNDS Robert Neville Haszeldine, Cambridge, England (Windyridge, Lyme Road, Disley, Cheshire, England) No Drawing. Filed Aug. 29, 1957, Ser. No. 680,915 Claims priority, application Great Britain Sept. 6, 1956 31 Claims. (Cl. 260-513) pending application Serial No. 526,087, filed August 2,

1955, Which is itself a continuation-in-part of my copending application Serial No. 377,716, filed August 31, 1953. Both of said applications are now abandoned.

By way of general introduction it may be stated that halogenated, particularly fluorinated, alkenes are becoming of increasing industrial importance. Thus, for example, the compound tetrafluoroethylene is of great value in synthetic organic fluorine chemistry and finds numerous industrial applications.

There are many other potentially valuable halogenoalkenes of which the classes of perfluorohalogenodienes and other fluorohalogenodienes may be cited as exemplary. In many cases industrial application of such halogenated dienes has been precluded or discouraged owing to the lack of commercially attractive methods of preparation. Thus for the 1,3-diene, hexafluorobutadiene, whose polymerization products are of potential importance, no really satisfactory method of preparation has hitherto been suggested.

It has now been found that certain primary halogenated compounds can be coupled by simple techniques to form longer chain compounds having various important uses, among which is included the production of halogenated dienes.

Specifically, the present invention provides methods of coupling compounds of the general formula where Z is selected from the class consisting of chlorine, bromine and iodine, Y is a halogen atom of no greater atomic weight than Z, X is selected from the class consisting of hydrogen and halogen atoms having no greater atomic weight thanZ and R is selected from the class consisting of alkyl, halogenoalkyl, alkenyl and halogenoalkenyl groups having from 1 to about 20 carbon atoms, cycloalkyl, halogenocycloalkyl, cycloalkenyl and halogenocycloalkenyl groups having up to about 6 carbon atoms, aryl and halogenaryl groups.

In one method according to the invention, the compound, or compounds, to be coupled are subjected to energization to raise the energy level of the compound or compounds sufficiently to cause fission of the CZ bond and formation of the free radical RCXY-. This may be accomplished in any convenient way; for example by heat, ultra-violet, infra-red, X, 'y, or high energy electron radiation, and the particular form of energization chosen will depend on the particular compound or compounds being reacted and on factors of convenience and practicability.

In accordance with this aspect of the invention, the reaction is preferably, but not necessarily, carried out in the presence of a halogen acceptor such as zinc, magnesium, tin, iron, cadmium, mercury and other metals;

NaOH, KI, Na S O and R SNa where R is an organic radical. In an especially convenient embodiment of the invention, the reaction is carried out using ultra-violet radiation in the presence of mercury.

Thereaction conditions used will vary greatly depending upon the reactants and the particular method chosen. Thus for example, where ultra-violet or other radiation is employed with or without a halogen acceptor the reaction may be carried out at from say -30 C. to 350 0, usually from room temperature to say 200 C. Where heat alone is used without other energization and with or without a halogen acceptor, the minimum temperature required to effect fission is normally on the order of 20 to 450 (3., usually between about 50 and about 280 C.

In the reactions according to the invention which are carried out by means of free radical mechanisms, i.e. by radiation or heat with or without a halogen acceptor, pressure is not an important factor and may range from say 0.1 mm. to superatmospheric, for example, to 500 atmospheres absolute. Normally pressures of 1 to 20 atmospheres are employed. Reaction time is again not critical and may be from 5 minutes to 5 weeks, depending on the temperature and pressure. In certain cases it may be desirable to carry out the free radical reactions in the presence of a solvent. When used, the solvent chosen should be one which is inert to the reactant or reactants and to the product or products. Other characterisics may be prescribed by the particular reaction being carried out; for example, where ultraviolet radiation is employed the solvent should be substantially transparent to radiation in the range 250-350 III/L. Often the reaction product is a suitable solvent. Examples of other useful solvents are perfluoromethylcyclohexane,

It will be understood, however, that where the coupling reaction is carried out by a free radical mechanism, the use of a solvent is not necessary and is simply a matter of convenience.

In an alternative process, according to the invention, the coupling may be carried out by bringing the compound, or compounds, to be coupled into contact with a dehalogenating metal, such for example, as zinc, magnesium, tin, iron, aluminum, copper or cadmium in the presence of a suitable solvent.

When the coupling is carried out by means of a dehalogenating metal, the metal attacks the CZ bond in the compounds to be coupled, removing the Z atom and in this way performing the function of the ultra-violet or other energizing agency in the first method referred to above. The reaction conditions which favor intermolecular, rather than intramolecular dehalogenation are in general provided by a temperature between about 20 C. and about 300 0., usually between about 0 C. and about 150 C., the precise temperature depending on the boiling point of the solvent used and on the pressure.

Generally speaking, moreover, higher temperatures within the stated range are used for intermolecular dechlorination than for debromination or deiodination. The pressure may range from sub-atmospheric, say 10 mm. Hg absolute to superatmospheric, say 100 atmospheres absolute. Normally 'it will be from about 100 mm. Hg to about 5 atmospheres absolute. The reaction time is not critical. To obtain a yield in excess of 60% it may range from 5 minutes to say 2 weeks, depending on temperature, pressure and the particular reactants.

Where a dehalogenating metal is to be used it is necessary to use a solvent. The solvent should be an organic compound preferably having a dielectric constant greater than 1.5. Preferably it will be a Lewis base, and preferably, though not necessarily, it will be free from acid hydrogens. Examples of suitable solvents are dioxan, benzene, acetic anhydride, and aliphatic monoand polyhydric alcohols having more than 2, say from 3 to carbon atoms such as propanol, glycerol, hexanol and decanol.

In the practice of the methods of the invention, it is preferred to effect the coupling reaction by intermolecular deiodination as opposed to debromination or dechlorrnation as the former is more readily achieved. Further, the substituents X and Y are preferably different, although X and Y may be the same; also it is preferred that X represent halogen as opposed to hydrogen. In general, it may be noted that the coupling of the compound RCXYZ to give RCXYCXYR occurs most easily when X and Y are iodine or bromine, less easily when X and Y are chlorine and least easily when X and Y are fluorine.

It may also be noted that the more halogen atoms in the R groups, the greater the ease with which the coupling reaction proceeds. Fluorine, chlorine and bromine substituents in the R group also promote the coupling reaction in increasing order.

With the above-stated considerations serving as a general guide, the optimum reaction conditions for the coupling of any given starting material will either be obvious or may be readily determined empirically.

As pointed out above the present invention deals with reactions between two compounds of the formula RCXY Z or two molecules of the same compound having that formula. Particularly preferred starting materials are halogenated alkanes, halogenated cycloalkanes and haloit being understood that the two Rs, the two Xs and the two Ys in this formula may be the same or different depending on whether two molecules of the same compound or one molecule of each of two different compounds are reacted.

Certain of these compounds have never before been prepared and exhibit useful and valuable properties. Thus, for example, compounds of the type where X is as defined above and R is selected from the class consisting of halogenoalkyl and halogenoalkenyl groups having from 3 to about 10 carbon atoms, and containing fluorine and at least one other halogen atom selected from the group consisting of bromine and chlorine; halogenocycloalkyl and halogenocycloalkenyl groups of from 3 to 6 carbon atoms and containing fluorine and at least one other halogen atom selected from the group consisting of chlorine and bromine; and halogenoaryl groups containing fluorine and at least one other halogen selected from the group consisting of chlorine and bromine, are considered to be new.

Other valuable new compounds are those in which R is perfluoroalkyl and perfluoroalkenyl of 3-10 carbon atoms; perfiuorocycloalkyl and perfluorocycloalkenyl of 3-6 carbon atoms and perfluoroaryl.

The novel compounds as will be developed more specifically below provide intermediates for the preparation of unsaturated compounds which may be polymerized to provide heat resistant plastics and lubricants and are useful per se as plasticizers for fluorinated resins, insecticides and as lubricants or lubricant additives.

In many cases, especially where the starting materials are halogenoalkenes, alkenes, cycloalkanes and cycloalkenes, the products of the coupling reaction may serve as valuable intermediates in the preparation, by intramolecular dehalogenation and/or dehydrohalogenation, of more highly unsaturated compounds, for example, straight or branched chain halogenated polyenes, particularly perfluorodienes, other fiuorodienes, perfluorochlorodienes and other fiuorochlorodienes. This aspect of the invention is exemplified later in considerable detail by the production, inter alia of hexafluorobutadiene by the coupling of a hexalogenoethane to yield a decahalogenobutane, this latter compound being dehalogenated to the desired hexafiuorobutadiene. The last compound may be polymerized to give oils which are stable to heat and chemical attack as well as plastic material having these properties.

In the production of straight and branched chain halogenated polyenes, particularly perfiuorodienes, other fiuorodienes, perfluorochl-orodienes and other fluorochlorodienes, according to the invention, many methods may be employed in preparing the necessary starting materials. However, such starting materials may in many cases be most fruitfully derived from alkenes, halogenoalkenes, acetylenes and halogenoacetylenes by addition to these compounds of iodine monochloride or monobromide, the addition product being subjected to a coupling and subsequent dehalogenation and/ or dehydrohalogenation reaction. Where the iodine halide addition reaction is selected for the preparation of starting materials, it should also be pointed out that the coupling reaction of the invention may occur to some extent in situ; this will be apparent from Example IV given hereinafter.

Considering first the application of the invention to the production of fiuorodienes, this may be exemplified by the preparation of the 1,3-diene, hexafluorobutadiene.

The preparation of hexafluorobuta-L3-diene in accordance with a preferred practice of the invention involves the coupling of either the compound CF ClCFClI (Compound -I) or CF BrCFCl=I (Compound II) to yield respectively, by the removal of one molecule of iodine, CF ClCFClCFClCF Cl (Compound III) or (Compound IV). Compounds III or IV are then dehalogenated to yield the desired hexafiuorobuta-1,3-diene.

The coupling step may be achieved, in this preferred operation, either by exposing Compounds I or II to the action of mercury and ultra-violet light or by treating a concentrated solution of such compounds in a solvent such as dioxan with a dehalogenating metal, e.g. zinc. Since the subsequent dehalogenation of the products of the coupling reaction may be effected in situ by treatment with zinc and a solvent such as dioxan at higher temperature, it is preferred to use this method for the coupling step also. In this manner the conversion of Compound I or II to hexafluorobuta-L3-diene can be brought about in one vessel by raising the temperature after the formation of the coupled product. It may be mentioned that irradiation of Compound I with ultraviolet light in the presence of mercury under relatively mild conditions yields CF ClCFClHgI, photolysis of which in an inert solvent such as perfluoromethyl cyclohexane gives the desired Compound III above.

The starting materials, i.e. Compounds I and II, in the process above described may be conveniently prepared by the addition reaction of iodine monochloride or monobromide, as the case may be, with commercially available chlorotrifluoroethylene. It has been established that such reaction does in fact yield compounds of the structure indicated. The reaction takes place readily under slight pressure, e.g. in an autoclave in the absence of a solvent, or somewhat more slowly when the chlorotritluoroethylene is passed through a suspension of the iodine halide in solvents such as carbon tetrachloride,

l,1,2-trichlrotrifluoroethane, 1,2-dibromo 1 chlorotrifluoroethane, or any fluoroor fluorohalo-compounds of suitable boiling point. The use of Compound I or 'II as reaction media has also been found convenient, since the necessity for subsequent efficient frictional distillation is thereby removed. As might be expected, the addition of iodine chloride occurs at a much lower temperature than that of iodine bromide. The reaction should be carried out in the absence of oxygen and to this end an atmosphere of nitrogen may be employed.

The only by-product from the addition of the iodine halide Ito chloro trifluoroethylene is the compound in which the iodine atom in Compound I or II has been replaced by chlorine or bromine respectively. This is ascribed to the reaction of chlorofluoroethylene with chlorine or bromine (formed by dissociation of the iodine halide into iodine and halogen), or to the secondary reaction of Compound I or II with the iodine halide or halogen. The by-products 1,1,2-trichlorotrifluoroethane and 1,2- dibromo-l-chlorotrifluoroethane are dehalogenated to chlorotrifluoroethylene in almost theoretical yield, so that the preparation of Compounds I and I I may be essentially quantitative.

It should be noted that the addition of an iodine halide 'to an alkene or acetylene does not necessarily constitute the only or most preferred method available for the preparation of compounds to which the coupling procedure may be applied. Among other methods available for the preparation of the starting compounds RCXYZ are those set forth below:

(a) The addition of compounds of the type R CXYZ to unsaturated linkages in acetylenic or alkene derivatives, R representing an organic group which need not necessarily contain halogen. The addition of R CXYZ to acctylenes or alkenes, including those containing halogen, may be effected by use of ultra-violet light or of a catalyst promoting free radical reactions (eg a peroxide), or by use of a catalyst promoting ionic reaction (e.g. a Friedel-Crafts type catalyst), or by any other means known to the art.

b) The addition of hydrogen fluoride, chloride, bromide or iodide or of fluorine, chlorine, bromine or iodine to unsaturated linkages in acetylem'c or olefinic derivatives.

(c) The halogenation by fluorine, bromine, chlorine or iodine of suitable compounds containing hydrogen.

(d) By metathesis reactions, e.g. by replacement of chlorine, bromine or iodine by fluorine.

(e)' By dehydrohalogenation, dehalogenation, hydrogenation, dehydrogenation, decarboxylation, etc. of suitable compounds.

(1) By the process described and claimed in my copending applications Serial No. 526,086, filed August 2, 1955, and its continuation-impart Serial No. 680,914, filed August 29, 1957. Reference may also be had to my UK. patent applications Nos. 23,106/54 and 15,157/55 filed respectively August 9, 1954, and May 25, 1955. As described in the above applications polymers and adducts of the general formula than 20 and m is an integer not greater than 30, can be made by reacting a fluoro alkene or a fluoro polyene with a perhalogeno ethane having the general formula According to the copending application referred to, this reaction may be carried out under the influence of ultraviolet radiation, under heat with an initiator, under heat 6 and ultra-violet radiation, under heat Without either ultraviolet or an initiator, or under the action of a radioactive initiator. Certain of the compounds so made can be coupled by the process described in the present application provided that the compound as a whole conforms to the formula RCXYZ set forth above.

(g) By the technique described by Hauptschein et al., Journal American Chemical Society, 79, 2549 (May 20, 1957). Again it will be understood that only those compounds which conform to the formula RCXY Z given above may be employed.

(It) By the process described in Hauptschein et al. copending application Serial No. 663,005, filed June 3, 1957, now abandoned, and its continuation-impart application Serial No. 773,551, filed November 13, 1958, now Patent No. 2,975,220 which describes polymers and adducts of various telogens With vinylidene fluoride, CH =CF The invention finds general application in the preparation of higher chain length halogenated compounds from those of lower chain length. Such compounds have many uses. Some may be useful as resin plasticizers, some may have biocidal (i.e. insecticidal, herbicidal, etc.) activity, and all are generally useful as intermediates.

The coupled products in accordance with the invention may be treated by normal dehalogenating or dehydrohalogenating procedures to give unsaturated compounds. Thus, for example,

where R is as defined above, X is selected from the group consisting of hydrogen, fluorine, chlorine, bromine, X is selected from the group consisting of bromine and chlorine and Z is bromine or iodine.

It in either of the above compounds, RCX'XZ', X is hydrogen, dehydrohalogenation may be performed in place of dehalogenation, viz:

RCHX"CXXR ldehydrohalogeuation One particularly useful application of the coupling procedure of the invention is the preparation of straight chain non-conjugated polyenes using a starting material of the type R CXYZ' in which R is a straight chain halogenoalkyl group having from 1 to about 20 carbon atoms. Depending on the chain length of the group R and the disposition of halogen atoms therein, successive dehalogenation or dehydrohalogenation reactions may be applied to the coupled product R CXYCXYR etc., to produce polyenes containing progressively more ethylenic linkages. This application may be illustrated as follows:

intermolecular deiodination intramolecular debromination C FF-C F (0 F2) 0 F010 F 01(0 FQRC F=C F; (Compound V) The same reaction may be represented more generally as follows:

dehalogenation or dehalogenation or dehydrohalogenation \Qehydrohalogenatron (11:0 (n= In the above equations, n is from 0 toand m is nl, Y -is fluorine, chlorine or bromine, Z is bromine or iodine, and X is hydrogen, fluorine, chlorine or bromine, provided that at least one X substituent on the C and C" carbon atoms is hydrogen, chlorine or bromine and that at least one X substituent on the carbon atoms adjacent the C and C carbon atoms is such as to be capable of forming with said one substituent on the C and C carbon atoms a molecule of the class C1 Br HCl, and HBr.

If in Compound V above the integer n is 0, a diene will result which may be further intramolecularly dechlorinated to give a triene, thus:

OFFOFCFCICFCICFZCFI Intrarnolecular dechlorination CF GFCF=CFCF=C Fr (Compound VI) This reaction typifies a further aspect of the invention which may be represented more generally as follows:

dehalogenation or dehydrohalogenation In the above equations 11 is from 0 to 20 X, X X and X are selected from the group consisting of hydrogen chlorine and bromine and not more than one of X and X and not more than one of X and X arehydrogen; X is from the group consisting of hydrogen, fluorine, chlorine, and bromine and Y is selected from the group consisting of fluorine, chlorine and bromine, provided that at least one of the X and Y substituents on each the C and C carbon atoms is selected from the group consisting of hydrogen, bromine and chlorine, and that when the X substituent on said C carbon atom is hydrogen, said C carbon atom has a substituent selected from the group consisting of chlorine and bromine.

Halogenated trienes of this type, i.e. trienes of the above formula where X is fluorine, chlorine or bromine, are new and exhibit properties which make them useful as intermediates as will be explained in more detail below.

Whether a diene or triene is obtained will depend on the structure of the original compound and on the conditions of reactionv Those skilled in the art can easily determine the conditions necessary to obtain the desired degree of unsaturation for any particular compound.

In a further aspect of the invention branched chain dienes may be prepared from a starting material R CXYZ wherein as before Z is iodine or bromine (preferably iodine), X and Y are as appropriate bromine, chlorine, or fluorine (although X can as stated he hydrogen) and R is a branched chain alkyl group or halogenated branched chain alkyl group. The coupling reaction is 7 2 followed by intramolecular dehydroh-alogenation and/or dehalogenation.

Branched chain dienes of particular interest which may be prepared in accordance with the process of the invention are represented by the general formula:

R: /R1 C=CXCX=C Formula 1 where X is as defined above and Rf and R are selected from the group consisting of alkyl, halogenoalkyl, alkenyl and halogenoalkyl groups having not more than about 17 carbon atoms, cycloalkyl and halogenocycloalkyl groups having up to about 6 carbon atoms, aryl and halogenoaryl groups. It will be understood that R, and R may be the same or different and that each R: and each R group may be the same as or different from the other R or R group. Compounds represented by the above formula are preferably perfluorodienes, other fiuorodienes, perfiuorochlorodienes and other fluorochlorodienes.

The general reaction for the production of such branched chain dienes may be represented as:

Rr\ 2 OX -CXY'Z coupling -L R1\ /R1 CX -CXYCX'lV-CX R, I I dehydrohalogenntlon dehalogfznation R1\ /R1 C=CXCX=C R, R, X in the above equation benig hydrogen, fluorine, chlorine or bromine, X being hydrogen, chlorine or bromine, Y being bromine, chlorine or fluorine and Z, as above, bromine or iodine, but in no case of less atomic weight than any other halogen in the compound to be coupled.

This type of reaction is exemplified below:

I intermolecular l l l CH C CFClI CH C C C O-CH I delodination I I l H H C1 C1 H intramolecular dehydrochlorination JF, F F CF; OH -C C C=C-CH;

A branched chain compound may also be coupled with a straight chain compound, as for example:

intramolecular ldechlorination or, F F r A more general representation of Reaction 2 above may be given as deha logenation and/or dehydrohalogenation 25 unsaturated linkage.

l derstood that in some coupling reactions using a dehalogenating metal, intramolecular dehalogenation will occur as a side reaction. When the nature of the initial compound to be coupled, RCXYZ, is such that internal dehalo- 5 genation is favored to the extent that the yield of coupled product is unacceptably small, the other coupling process, i.e. energization to produce free radicals, is used.

Dehydrohalogenation reactions may be carried out by conventional procedures using alcoholic KOH or NaOH.

In such reactions the temperature is normally between Such polyenes are also important products of the present invention.

Polyenes of a somewhat different type can also be made by a coupling reaction according to the invention, where each of the two compounds coupled has more than one Such compounds include those having the general formula R, C (R )2 0 P):

R! In the above equations, Y is fluorine, chlorine or bromine, Z is bromine or iodine, n is from 0 to 20, R and R are as defined above, X and X are hydrogen, chlorine or bromine, and X is hydrogen, fluorine, chlorine, or bromine, provided that no more than one of X and X is hydrogen and provided further that at least one of the X atoms on said C carbon atom is hydrogen, chlorine or bromine and that the carbon atom adjacent to the C carbon atom has at least 1 atom subtended therefrom which is capable of forming with said one X' atom on the C carbon atoms, a molecule of the group HCl, HBr, C1 and Br The intramoleoular dehalogenation or dehydrohalogenation reactions discussed above may be carried out using any conventional technique. Dehalogenation is normally accomplished by bringing the compound into reactive association with a halogen acceptor, for example, zinc dust, iron, magnesium or sodium amalgam. The reaction is preferably carried out in the presence of a solvent for the organic compounds involved. Examples of suitable solvents are alcohols such as methanol, ethanol, butanol, tetrahydropyran and tetrahydrofuran, glycols such as ethylene glycol; ethers and substituted amides.

The temperature at which the reaction occurs is normally the reflux temperature of the particular solvent used. Dehalogenation reactions may, however, be carried out at room temperature or below and in general the reaction temperature may range from 0 to say 200 C., normally between about C. and about C. Pressure is not critical and may range from say 200 mm. Hg absolute to 50 atmospheres. Normally, however, it will be from about 1 to about 20 atmospheres. Reaction time is again not critical. It may range from say 20 minutes to a week and is usually on the order of /2 to 10 hours.

It will be observed that the conditions just given for intrarnolecular dehalogenation overlap those previously given for intermolecular dehalogenation. It will be unwhere R is selected from the group consisting of hydrogen, fiuorine, chlorine, bromine, alkyl, halogenoalkyl, alkenyl and halogenoalkenyl groups having from 1 to 20 carbon atoms, cycloalkyl, halogenocycloalkyl, cycloalkenyl and halogenocycloalkenyl having from 3 to 6 carbon atoms; aryl and halogenoaryl, where R, is selected from the group consisting of hydrogen, fluorine, chlorine, bromine, alkyl and halogenoalkyl of say one to four carbon atoms, where X is hydrogen, fluorine, chlorine, or bromine and where Y is fluorine, chlorine, or bromine.

Still another group of useful compounds can be prepared according to the present invention from certain specific types of the polymeric materials whose preparation and pro erties are described in my copending application Serial No. 526,086 referred to above, and its conurination-impart application Serial No. 680,914, filed August 29, 1957, now abandoned.

As pointed out above, the compounds described in 0 said copending application include polymers and adducts of the general formula CF XCClY"(R Z Where X" is chlorine or bromine, Y" is chlorine or fluorine, Z is as described above, R is fluoroalkene and n is from 1 to about 20.

Of this general class, however, only certain types of compounds are suitable for the coupling reactions de scribed herein. In general, it may be said that the compound must conform to the structure RCXYZ set forth earlier in this application. Thus, the polymers and adducts subjected to coupling are those in which the fluoroalkene is such that its terminal carbon atom, i.e. the carbon atom joined to the Z atom, has one halogen substituent of no greater atomic weight than the Z atom and another substituent which is either halogen of no greater atomic weight than Z or hydrogen, it being also necessary that the starting molecule contain no other halogen substituents, particularly the halogen substituent X" in the above formula, which are more reactive than the Z halogen. For convenience, such polymers or adducts may be represented as:

where X", Y" and Z are as defined above, R is a fluoro alkene radical having the qualifications as to halogen a sence content given above and r is an integer not greater than 20. Examples of -(R groups in the above formula are the following: --(CF CFCl),, '(CF CF -(CFCCl -(CF CHC1) (CH CHF) --(CH CF and -(CGFCF Referring first to coupling reactions involving these polymers and adducts, the general reaction may be written Cl(CF CFCl 1 +1 (CFClCF H 01 C1 (CF CFCI) (CFClCF Cl The coupled compounds so made may be subjected to dehalogenation to give a diene, such reaction being shown below intramoleeular dehalogenation oF,=oY"(R,) (Rm) oU=o F; It is to be understood that the chain (R (R must be less susceptible to dehalogenation than the CF X"CClY" and CF QCClU groups under the conditions used for intramolecular dehalogenation. Typical groups from which R and R may be chosen are -CF CFCI, CF CF -CH CF and -CH2CFC1.

If the (R and (R groups are such that their terminal carbon atoms, i.-e. the carbon atoms next to the Z and Z atoms in the formulae CF XCClY"(R Z' and CF QCClU(R Z" each have a halogen other than fluorine attached thereto, the triene can also be made by dehalogenation, thus oF2=o F"(R -iRnXX"OX'X"RO(R,,,) 1CU=CF,

intramolecular dehalcgenation CF2=C F"(Ri)s-iRni7=( -Ro(Rm)q-iOU=G F; where 'R is R less its terminal carbon atom and R is R less its terminal carbon atom, and X and X are as defined above.

The dehalogenation reactions disclosed generally above are illustrated by the following specific reaction:

In carrying out the dehalogenation reactions, the conventional techniques disclosed above are employed.

Whether a diene or a triene is obtained will depend on the structure of the original polymer and on the condii2 tions of reaction. Those skilled in the art may easily determine the reaction conditions necessary to obtain the desired unsaturated compound for any particular polymer.

The above-described terminally unsaturated compounds may be oxidized, e.g. with aqueous KMnO to form dicarboxylic acids.

The general reaction may be Written as l oxidation HO 0 C (Rj)p(Rm)qC 0 OH it being understood that the chain (R (R is less susceptible to oxidation than the end groups CF CY and CF =CU-. Suitable values for R and R will in clude -CF CF and 2".

Illustrative of this type of reaction is the following specific reaction:

0 F =G F (0 F10 F 01) ,(G FGIC F2) O F=O F,

loxidatlon with aqueous KMnO;

Further, it has been found possible to produce perfluorodicarboxylic acids by oxidation of a terminally unsaturated perfluoro triene; this reaction may be utilized as described in detail later for the preparation of the new compound pertluoromalonic acid.

In another type of oxidation reaction, a terminally unsaturated triene disclosed above may be split to give two di-basic acids. This reaction is feasible when X in the appropriate formula given above is chlorine or fluorine and may be written as follows:

This may be illustrated by the oxidation of particular trienes whose preparation is described above. Thus:

C FFC F (C F C FCDn-IC F20 FC FAG F CIC F1)qiC F=C F loxidation (KMHOA) HO O C(CF CFCDp-iCFaCOOH HOOCCFg(CFClCF:)a-2COOH In carrying out the oxidation reactions described above, no special technique is required. Various conventional oxidizing agents such as alkali metal permanganates, e.g. potassium permanganates, alkali metal dichromates, e.g. potassium dichromate or ozone may be used but potassium permanganate is the preferred agent using the technique described by Haszeldine in Journal of the Chemical Society 4259 (1952).

The reaction is preferably carried out at a slightly elevated temperature, for example, at 30-60" C. or up to 200 C., but may be carried out at room temperature or even below room temperature, to say 0 C. Pressure is not critical and may be atmospheric or up to say 50 atmospheres. Reaction time is whatever is required to complete the particular oxidation being carried out. It is usually on the order of one to several hours but may be up to 5 days.

The dicarboxylic acids whose preparation has been described above may be converted to their corresponding silver salts and these salts may then be subjected to reaction with halogen whereby they undergo decarboxylation with simultaneous halogenation to give substantial yields of a halogeno alkane. Although this reaction is known for the silver salts of perfluoro acids it was surprising to find it proceeds also with the silver salts of poly- 1.3 This novel reaction may be written sC( p)( q)000Ag i p)( q) Where R and R are polyfluoro chloroalkyl groups having from, 2 to say 40 carbon atoms and Z is as defined above.

This reaction is normally carried out under anhydrous conditions at a temperature that may range from about 30 C. to about 250 C., depending on the halogen used. Subatmospheric pressure is employed, ranging from 0.01 to say 500 mm. Hg absolute. Proportions are not critical and may range from 0.1 to 10 moles of halogen per mole of salt. Preferably, however, an excess of halogen is employed. The reaction time is normally from about /2 to about 24 hours.

It should be noted that the decarboxylation also proceeds with unsaturated polyfluorochloro dicavboxylic acids although in this case where the halogen Z is bromine or chlorine some halogen addition may take place to the unsaturated group or groups in the starting compound.

The polyfiuorochloro dicarboxylic acids may also be converted to the corresponding alkali metal salts which on subjection to pyrolysis yield dienes having two less carbon atoms than their precursors. The pyrolysis reaction which applies also to polyfluorobromo dicar-boxylic acids, may be illustrated by the important new general and specific reactions given below:

MO 00 C IMO FXR.RtC FX 'd F C 0 0M lHeat om=o Frame F=O F; 2MX 2o 02 where M is an alkali metal such as sodium or potassium, and R and R, are polyfluoro groups or polyfluorochloro groups, for example, polyfluoroalkyl or polyfluorochloro- *alkyl groups having up to say 40 carbon atoms. The

cases where R and R are perfluoro or perfluorochloroal-kyl groups of 1 to carbon atoms are of particular interest.

As an example of a specific reaction the following may be given:

M000 0 F20 F 01(0 F20 F Cl)p(C F010 F2) C F 010 F 0 0 0M reaction; thus it is'possible to produce the corresponding trienes of the formula In the general pyrolysis reaction given above, a note- -worthy point (when Z=Cl), is the elimination of a ,8 I chlorine atom which results in a chloride by-product such as sodium chloride as opposed to a fluoride by-product which is produced when perfluorocarboxylic acids are pyrolyzed and which must then be recovered on economy grounds; sodium chloride being cheap may be simply discarded as a waste product.

The pyrolysis is preferably per-formed under anhydrous conditions at temperatures .of from about 50 C. to about 350 C. The pressure is usually atmospheric or less, preferably between about 1 and about 350 mm. Hg absolute.

Instead of converting the terminally unsaturated coupled adducts and polymers described earlier into car- 14 boxylic acids and derivatives of such acids, they may also be converted into surface active sulphonic acids and sulphonates, for example, by reaction of the terminally unsaturated compounds with an alkali metal bisulphite, particularly sodium bisulphite, followed by treatment with sulphuric acid if the free acid is desired.

I This reaction may be written where M is an alkali metal, R R Y and U are as defined above and p and q are integers not greater than 20.

This reaction is preferably carried out in an aqueous medium in the presence .of 'a peroxide initiator. As examples of suitable initiators there may be cited benzoyl peroxide, ,7 acetyl peroxide, hexachloroacetyl peroxide, hexafluoroacetyl peroxide, di-tertiarybutyl-acetyl peroxide, a,a-azo-diisobutyronitrile and di-azomethane. The initiator is preferably used in a concentration of say 1- 10% on the weight of the unsaturated compound. The reaction temperature maybe from about 20 C. to about 300 0, preferably from about 50 C. to about 200 C. Pressure is not critical and may range from say mm. absolute to on the order of 200 atmospheres. Preferably pressures of from atmospheric to about 30 atmospheres are used. The reaction time depends on the other conditions. Normally it is on the order of one to 48 hours.

It has further been found that a specific group of compounds of the general class namely those having the formula where Y is chlorine, bromine, or fluorine, Where X" is bromine or chlorine, where Z is bromine or iodine, where R and R are hydrogen, halogen, alkyl, or halogenoalkyl having up to about 10 carbon atoms, and n is not greater than about 20, can be reacted with molecular oxygen to give compounds of the general type and that along with these carboxylic acids there may be formed coupled compounds of the general formula This oxidation may be carried out using oxygen and ultraviolet light with or without heat, oxygen with heat and an initiator such as one of the peroxide initiators listed above or with heat and oxygen alone. When ultraviolet light is used, the reaction temperature will usually range from room temperature (20 C.) to about 200 C., preferably from 20 C. to about 100 C. When heat alone is used to initiate free radical formation higher temperatures will be necessary, e.g. between about 50 C. and about 350 C., preferably between about 100 C. and about 250 C.

Pressure is not critical and may be from say 10 mm. Hg absolute to 50 atmospheres, usually from 0.5 to 15 atmospheres. The reaction time may vary from /2 hour to say one week, normally from about 5 hours to about three days. Normally between about 0.1 and about 10 moles of oxygen (0 will be present per mole of fluoro compound.

Such reactions carried out in the presence of molecular oxygen are thus another method of performing the coupling described above.

More generally stated, a third method of coupling is provided in which compounds of the type t may be reacted with one another in the presence of molecular oxygen to give products of the type where R is perfluoro-, perfiuorochloroalkyl or perfiuorobromoalkyl of say 1 to 20 carbon atoms, perfluorocycloalkyl, perfluorochlorocycloalkyl or perfluorobromocycloalkyl of say 3 to 6 carbon atoms, perfiuoroaryl, perfiuorochloroaryl or perfiuorobromoaryl. X" is chlorine or bromine, Y is fluorine, chlorine or bromine, Z is bromine or iodine, R and R are hydrogen, halogen, alkyl or halogenoalkyl of 1-10 carbon atoms and n is from 1 to say 20. The oxidation reactions are described more fully in my said copending application Serial No. 526,086, filed August 2, 1955, and its continuation-in-part application Serial No. 680,914, filed August 29, 1957.

In addition to the telomers and adducts listed above which may be made according to my copending application, the process of the present invention is applicable in general to compounds of the type described in the Hauptschein et al. article refen'ed to above and in Hauptschein et al. Patent No. 2,975,220. The Haupt- 'schein et al. article describes the formation of telomers and adducts of difiicultly telomerizable olefins and diolefins. Such telomers and adducts may be employed in the present process, provided they conform to formula RCXYZ given above.

Hauptschein et al. Patent No. 2,975,220 deals with certain adducts and telomers of vinylidene fluoride, such for example as where Z is as defined above and n is from 1 to 20. These compounds may be coupled in accordance with the pres ent invention and the products so obtained include, as brought out in the above application, valuable lubricants showing exceptionally good temperature-viscosity characteristics. In general therefore the invention includes as new compositions of matter, products of the formula r( m) 'r where R; and R are as defined above and R and R' are selected from the group consisting of fiuoroalkyl, fluorochloroalkyl, fluoroalkenyl and fluorochloroalkenyl radicals of 1-20 carbon atoms, fluorocycloalkyl, fluorochlorocycloalkyl, fluoroalkenyl and fluorochlorocycloalkenyl groups of 3-6 carbon atoms and fluoro and fluorochloroaryl groups. The fluorobromo compounds in each of these categories are also of value. Of particular interest, however, are the perfluoro and perfluorochloro groups. For practical purposes these compounds and indeed all the compounds discussed in this application will have not more than around 50 carbon atoms in the molecule. Higher chain lengths can be made, but since the uncoupled products are usually solids to begin with the coupling reaction is d-iflicult to carry out and the products are generally not as useful as those having 50 or less carbon atoms in the molecule.

In addition to the above noted examples of compounds that may be coupled in accordance with my invention, a number of other exemplary compounds of the type RCXYZ are listed below:

1 6 CC1 =CFCHBrI CFCFCIBT By way of illustration, the following examples are given which show the practice of the invention as applied Chlorctrifiuoroethylene was condensed into an evacuated steel bomb fitted with needle valve and pressure gauge, and containing an equivalent amount of iodine monochloride. The bomb was sealed and warmed to 35-40 C. to melt the iodine monochloride. An exothermic reaction set in on shaking, and the pressure reached a maximum of 9 atmospheres before dropping rapidly to atmospheric pressure. The initialed reaction was complete after ten minutes and, after standing for two hours, the contents of the bomb were removed by pumping through a trap cooled in liquid air. All the chlorotrifiuoroethylene had been converted into a liquid product which, after treatment with sodium thiosulphate to remove traces of iodine, was dried (phosphoric anhydride) and distilled to give 1,1,2-trichlorotrifluoroethane (1% yield), B.P. 47.5-48.0 C., 11 1.355, and 1,2- dichloro-1,2,2-trifluoroiodoethane (97%). (Found: C, 8.7; M, 275,280, C Cl F I requires C, 8.6%; M, 279), B.P. 9999.5 C., 11 1.4449, a colorless liquid turning pink on exposure to light. Ultraviolet absorption spectrum in ethanol; A max. 261 me, e295; A min. 233 m 6190. (e=molar extinction coeflicient.)

In another preparation, the bomb containing iodine 1 monochloride was evacuated, heated to 30 C. and connected by a flexible metal pressure tube to a cylinder of chlorotrifluoroethylene. The olefin was slowly admitted to the continuously shaken bomb at such a rate that the temperature did not rise above 40 C., until no more was absorbed (2 hrs.). The excess chlorotrifiuoroethylene was removed, and the contents of the bomb were distilled to give 1,2-dichloro-1,2,2-trifiuoroiodoethane (96% A small amount of iodine was left in the bomb.

In reaction at atmospheric pressure, chlorotrifiuoroethylene was passed by means of a dispersion disc into a stirred suspension of iodine monochloride in previously prepared 1,2-dichloro-1.,2,2-trifiuoroiodocthane warmed to 45-50 C. The unchanged olefin was recycled, and after a total of four hours no further absorption occurred. After removal of iodine with sodium thiosulfate, the yield of distilled 1,2-dichloro-1,2,2-trifiuoroiodoethane was 87%, and of l,1,Z-trichlorotrifluoroethane was 6%.

The 1,1,2-trichlorotrifiuoroethane formed as a by-prodnet in the above experiment was reconverted to chlorotrifiuoroethylene in yield by treatment with zinc and ethanol.

THE COUPLING OF THE 1,2-DICHLORO-1,2,2-

TRIFLUOROIODOETHANE 1,2-dichloro-1,2,2-trifluoroiodoethanc and about an equal volume of mercury were sealed in an evacuated silica tube which was then shaken horizontally by means of a vibro-shaker. Intimate mixing of the mercury and iodo-compound was thereby obtained, and upon exposure to ultraviolet light from a Hanovia are situated 5' cm. from the reaction vessel, mercuric iodide was rapidly deposited. Use of an excess of mercury prevents coating of the walls of the vessel by mercuric iodide. After 48 hours the liquid contents of the tube were transferred by heating and pumping to a cooled trap, then distilled to give unchanged 1,2 dichloro 1,2,2 trifluoroiodoethane (5%), B.P. 99100 C., 1,2,3,4-tetrachlorohexafiuorobutane (82% yield based on iodo-compound taken),

17 found: C, 15.6; CI, 46.4; C Cl F requires C, 15.8; CI, 46.7%), B.P. 134.0-134.5 C., 75 C./l06 mm., 11 1.382, and an unidentified by-product (ca. 7%); B.P. ca. 95 C./30-mm., n 1.394.

A similar experiment, carried out in a silica tube which was rocked gently during reaction, gave an 85% yield of l,2,3,4-tetrachlorohexafluorobutane (89% yield based on the iodo-compound used) (95%) after 48 hours.

The experiment was repeated with the tube stationary during irradiation. The mercury/ organic liquid interface became covered with mercuric iodide and after 48 hours, examination of the liquid reaction products showed them to consist of 1,2,3,4-tetrachlorohexafluorobutane (71% yield) and unchanged 1,2-dichloro-1,2,2-trifluoroiodoethane The ethereal extract of the solid products yielded, after removal of the ether and sublimation of the residual solid, 1,2-dichloro-l,2,2-trifluoroethyl mercuric iodide (12% yield). (Found: C, 5.2; I, 26.0; C Cl F IHg requires C, 5.0; I, 26.5%), white plates recrystallized from chloroform to M.P. 92-94 C. and with an odor similar to that of trifluoromethyl mercuric iodide. On exposure to ultraviolet light while suspended in perfluoromethylcyclohexane, the mercurial was converted into mercuric iodide and l,2,3,4-tetrachlorohexafluorobutane (61% yield).

PREPARATION OF HEXAFLUOROBUTA-1,3-DIENE To a well stirred suspension of zinc dust in ethanol (about 50% zinc) heated under reflux in a vessel fitted with an efficient water condenser leading to traps cooled in liquid air, was added dropwise over five hours 1,2,3,4- tetrachlorohexafiuorobutane in ethanol in the proportion of 30 parts of the halobutane to 100 parts zinc. Steady gas evolution took place, and after a further two hours the contents of the liquid air traps were passed through 5% sodium hydroxide and distilled in vacuo to give hexafluorobuta-1,3-diene (98%). (Found: C, 29.5; M, 162; calc. for C 1 C, 29.6%; M, 162), B.P. 5.8 C.

Example II COUPLING OF 1,2-DICHLORO-1,2,2-TRIFLUOROIODO- ETHANE AND CONVERSION INTO HEXAFLUORO- BUTA-1,3-DIENE IN ONE VESSEL To a vigorously stirred suspension of zinc and dioxan at 2530 C., was slowly added 25% of a solution of 1,2- dichloro-1,2,2-trifluoroiodoethane in dioxan. After a further 20 mins., the temperature was slowly raised to 50 C. (or to 100 C. to produce hexafluorobutadiene), and after cooling to 25 C. again, a second 25% of the iodo-compound solution was slowly added. This cycle of operations was repeated until complete addition of the chlorofluoroiodide had been achieved. Altogether 17 parts of iodo-compound were added to 30 parts zinc. The

. volatile products 'at this state were chlorotrifluoroethylene (40%) and a trace of hexafluorobuta-l,3-diene. Care' must be taken with the intermolecular deiodination carried out in this way. If the temperature is too low, or the solution of iodo-compound too dilute, little deiodination occurs initially and when the temperature is raised a very vigorous reaction sets in which leads almost completely to chlorotrifiuoroethylene formation. If the temperature is too high, intramolecular dehalogenation occurs to the exclusion of intermolecular deiodination. The intramolecular dehalogenation is favored in ethanolic solution and the use of dioxan, benzene or a higher alcohol is advantageous.

Thev 1,2,3,4-tetrachlorohexafluorobutane formed by the intermolecular deiodination is converted into hexafluorobuta-1,3-diene by raising the temperature of the dioxan solution to give a reflux. The total yield of hexafluorobuta-1,3-diene, separated from chlorotrifluoroethylene in a vacuum system is 60% 18 Example 111 ADDITION OF IODINE BROMIDE AND CHLORO- TRIFLUOROETHYLENE Chlorotrifluoroethylene (11.65 parts) and iodine monobromide (23 parts) in a steel bomb were heated from 30 to 100 C. over a period of 2 hours. Preliminary experiments had shown that there was incomplete reaction at 60 C. for a similar period, but that reaction was essentially complete at C. for 6 hours. Distillation of the contents of the bomb gave unchanged chlorotrifluoroethylene (2%), 1,2-dibromo l chlorotrifiuoroethane (4% yield). (Found: C, 8.6; calc. for Br ClF C, 8.7), B.P. 9292.5 C., n 1.425 and l-bromo-Z- chloro-l,1,2-trifluoroiodoethane (84% yield). (Found: C, 7.5; C BrClF I requires C, 7.4%), B.P. 82 C./ 195 mm., 11 1.482. The last compound is partly decomposed by distillation at atmospheric pressure but can be distilled in the dark under partial vacuum as a colorless liquid which readily liberates iodine on expostu'e to light.

THE CONVERSION OF 1-BROMO-2-CHLORO-1,1,2-TRI- FLUOROIODOETHANE INTO HEXAFLUOROBUTA-1,3- DIENE Mercury (130 parts) and 1-bromo-2-chloro-1,1,2-trifluoroiodoethane (16.2 parts) were sealed in a silica tube which was shaken vigorously and exposed to ultra-Violet radiation for 3 days. The liquid products were separated from mercuric iodide by heating and pumping into a PREPARATION OF CF2C1CC12I AND CFzBrCClzI 1,l-dichlorodifluoroethylene (12.1 parts) was condensed in an evacuated steel bomb containing iodine monochloride (20 parts). The bomb was sealed and warmed to 40 C., at which temperature it was maintained for 2 hours. The temperature was slowly raised to C., then reduced to 20 C. The reaction products were distilled' 'to give:

(1) Unchanged CF =CCl 10% yield.

2 CF ClCCl B.P. 91" c.- 15% yield.

(3) CF ClCCl I (1,l,2-trichloro-2,2-difluoroiodoethane), B.P. 77 C./ mm. ca. 133 C./760 mm.-63% yield. (Found: C, 8.2, C Cl F I' requires, C, 8.1%.)

(4) CF ClCCl CCl CF Cl (1,2,2,3,3,4-hexachlorotetrafluorobutane), B.P. 143 C./ mm.-l0% yield. (Found: C, 13.9, C Cl F requires C, 14.2%.)

Addition of iodine monobromide to 1,1-dichlorodifluoroethylene similarly gave l-bromo-2,2-dichloro-l,1- difiuoroiodoethane (CF BrCCl I), B.P. 80 .C./50 mm. (Found: C, 7.1, C BrCl F I requires C, 7.05%), as well as 1,2-dibromo-l,l-dichlorodifluoroethane (CF BrCCl Br) M.P. 46 C., B.P. 139140 C., and 1,4-dibromo 2,2,3,3- tetrachlorotetrafluorobutane (CF BrCCl CCl CF Br) B.P. 8085 C./ca. 2 mm.

It will be noted from the above experimental results and from some of those given hereinafter that some coupling occurs during the addition reaction of the iodine On exposure to ultra-violet light at 20 C. for 48 hours, OF ClCCl I (10 parts) and mercury, vigorously shaken together, gave mercuric iodide and identical with that obtained above. The yield was 87%.

Coupling of CF BrCCl I similarly gave cFzBl' identical with that obtained above, in 64% yield.

DEHALOGENATION OF CFgClCClZCClZCFZCl The compound CF ClCCl CCl CF Cl (10.1 parts) dissolved in ethanol (20 parts) was added to zinc dust (50 parts) in ethanol (100 parts) heated in an apparatus with reflux condenser maintained at 80 C. so that ethanol and material of B.P. 80 C. slowly distilled through the condenser and was collected in water (400 parts). After addition of all the CF ClCCl CClgCF C1, the temperature of the reaction flask was raised until only ethanol was passing through the reflux condenser. The product collected as a lower layer in the water and was washed with a further quantity of water, dried over P and distilled to give in 83% yield, 2,3-dichlorotetrafluorobuta-1,3-diene (CF =CClCCl=CF B.P. 65 C. (Found: C, 24.8; M, 195. C Cl F requires C, 24.6%; M, 195.)

1,1,2-trichloro-2,Z-difluoroiodoethane can be converted into 2,3-dichlorotetrafluorobuta-1,3-diene in situ by application of the procedure of Example II, with the modification that between the portionwise addition of the solution of CF ClCCl I, and also finally, the temperature is raised to cause the dichlorotetrafiuorodiene to distill through a reflux condenser maintained at 80 C. for collection under water to remove traces of dioxan. CF ClCCl I (15 parts) was thus converted into CF =CClCCl=CF in 58% yield. The main by-product was CF =CCl (32%).

On reaction with chlorine, the CF =CClCCl=CF absorbed 2 moles to give CF ClCCl CCl CF Cl identical with the material described earlier.

Example V PREPARATION OF CFC12CC12I 9.7 parts of 1,1,2-trichlorofiuoroethylene were treated with iodine monochloride (90% of theory for addition) by the procedure outlined for CF =CCl in the preceding example. The products were:

(1) CFCI CCI I (1,1,2-tetrachloro-1-fiuoroiodoethane), B.P. 100-103 C./ca. 100 mm. 40% yield. (Found: 1, 40.0. C CI FI requires I, 40.7%

(2) CFCl CCl B.P. 139-140 C., a solid33% yield.

(3) CFCI CCI CCI CFCI (1,4 difiuorooctachlorobutane), B.P. 150C./18 mm., 100 C./ca. 2 mm., 21% yield. (Found: CI, 75.7. C Cl F requires CI, 76.8%.)

COUPLING OF CFClzCClzI Treatment of 5 parts of CFCIQCCIZI dissolved in CF ClCFCl (1,1,Z-trichlorotrifiuoroethane) solution with mercury and ultra-violet light as described for CF ClCCl I in Example IV gave, after 12 hours, an 82% yield of CFCl CCl CCl CFC1 1,4-difiuorooctachlorobutane) DEHALO GENATION OF CFClaCClzCChCFCla 5.3 parts of CFCl CCl CCl CFCl were dissolved in ethanol parts) and added in four batches to zinc (20 parts) and ethanol (30 parts). The temperature was slowly raised to 80-90 C. for 1 hour between each batch, then cooled to 20 C. before addition ofthe next batch. The ethanolic solution was filtered, an excess of water was added, and the lower layer dried over P 0 and distilled to give in 71% yield CFCl=CClCCl=CFCl 20 (1,2,3,4-tetrachlorodifluorobuta-1,3-diene), B.P. 82 C./ mm., 142 C./760 mm. (Found: C, 20.6. C Cl F requires C, 21.0%.)

Addition of 2 moles of chlorine to the diene gave C1-"Cl CCl CCl C1- Cl identical with the starting material for the dehalogenation step.

Example VI PREPARATION OF CFClzCFClI The addition of iodine monochloride (10% excess) to 1,Z-dichloroditluoroethylene (11.3 parts) was effected as described for CF =CCl in Example IV, and gave 74% of 1,1,2-tricl1loro-1,2-difluoroiodoethane, CFCl CFClI, B.P. 80-81" C./ 100 mm. (Found: I, 42.7. C Cl F I requires I, 43.0%.)

COUPLING OF CFClzCFCII 7.1 parts of CFCI CFCII were dissolved in CF CICFCI (5 parts), vigorously shaken with mercury while exposed to ultra-violet light, and gave CFCI CFClCFCICFCI (1,1,2,3,4,4-11exachlorotetrafluorobutane) in 78% yield. B.P. 136 C./l02 mm., 123 C./73 rnm. (Found: Cl, 63.4. C Cl F requires C1, 63.2%.)

DEHALOGENATION OF CFCI2CFCICFC1CFC12 Treatment of 6.8 parts of CFCl CFClCFClCFCl with Zinc and ethanol as described for the dehalogenation of CF CICCI CCl CF CI in Example IV gave CFCl=CFCF=CFCl (1,4-dichlorotetrafluorobuta-1,3-diene), B.P. 7S-76 C. in 78% yield. (Found: Cl, 36.4; M, 195. C Cl F requires Cl, 36.4%; M, 195.)

The diene absorbed chlorine (2 moles) to give the same hexachlorotetrafluorobutane as was used for the dehalogenation step.

The coupling of CFCl CFClI to give (CFCl CFCD followed by dechlorination was effected in one process by reaction of the iodo-compound with zinc and dioxan or benzene, as described above for CF ClCFClI modified as described for CF CICCl I in Example IV. The yield of the diene was 49%.

Example Vll COUPLING OF CF2ClCCl I WITH CFCleCChI Equimolar amounts of CF CICCL I and CFCl CCl I (total 10.1 parts) were dissolved in CF ClCFCl (5 parts) and vigorously shaken with mercury in a silica tube for 58 hours while exposed to ultra-violet radiation. The resulting solution was decanted from the mercuric iodide formed, which was washed with CF CICFCI (2 parts), and the combined solutions were distilled to give:

('1 CF ClCFCl solvent (2) CF ClCCl CCl CF Cl26% yield (cf. Example IV) (3) CFCl CCl CCl CFC1 28% yield (cf. Example V) (4) CF ClCCl CCl CFCl -42% yield, B.P. -113" C./ 15 mm.

(Found: Cl, 70.1. C Cl F requires Cl, 70.3%.)

DEHALO GENATION OF CF2ClCC12CC12CFCl-a Treatment of the compound (5.3 parts) with zinc and ethanol as described for the dehalogenation of in Example V gave 1,2,3-trichlorotrifluorobuta-1,3-diene (CF =CClCCl=CFCl), B.P. 104.5-105.5 C. in 61% yield. (Found: Cl, 49.9; M, 210. C Cl F requires Cl, 50.4; M, 211.5.)

Example VIII COUPLING OF CFzClCClzI WITH CFzClCFClI Equimolar amounts (9.3 parts total) of CF CICCI I and CF ClCFClI were dissolved in CF ClCFCl (5 parts) and treated as for the coupling of CF ClCCl I and CFCI CCI I described in the preceding example. Distillation gave:

( 1) CF ClCFCl solvent 41% yield, B.P. l50153 C./500 mm, ca. 173 C./760 mm. (Found: CI, 55.1. C CI F requires Cl, 55.4%.)

I DEHALOGENATION F CF2CICFCICCI2CF2CI CF ClCFClCCl CF Cl (4.7 parts) was dehalogenated by slowly adding its solution in ethanol (5 parts) to zinc parts) and ethanol parts) heated in an apparatus whose reflux condenser was maintained at 60 C. to permit the removal of the 2-chloropentafluorobuta-1,3- diene (CF =CFCCl=CF which was collected under water and redistilled from P 0 in a vacuum system. B.P. ca. 38' C. Yield 80%. (Found: Cl, 19.6; M, 179. C C1F requires Cl, 19.9%; M. 178.5.)

Example IX COUPLING OF CFClzCCIzI WITH CFzClCFClI Equimolar amount of CFCl CCl I and CF ClCFCII (7.7 parts total) dissolved in CF CICECI (5 parts) and treated as described for the coupling of CF ClCCl I and CFCl CCl I in Example VII, gave on distillation: 1 Solvent (2) CFCl CCl CCl CFCl 41% yield (cf. Example V) (3) CF ClCFClCFClCF Cl-39% yield (cf. Example I) (4) 1,1,2,2,3,4-hexachlorotetrafluorobutane (CF C1CFClCCl CFCl B.P. 120 C./79 mm., 51% yield. 63.3. C Cl F requires Cl, 63.2%.) DEHALOGENATION OF CFgCICFCICChCFCIZ Dehalogenation of 4 part of CF CICFCICCl CFCI was effected in'53% yield by the procedure given for CF ClCCl CCl- CF Cl in Example IV, to give 1,2-dich1orotetr'afluorobuta-1,3-diene (CF =CFCCl=CFCl), B.P. ca. 68 C. (micro). (Found: C1, 35.9; M, 195. C Cl F require Cl, 36.4; M, 195).

Example X COUPLING OF CFzClCFCII WITH CFCIgCFClI 8.3 parts of an equimolar mixture of CF ClCFClI and CFCI CFCII were dissolved in CF ClCFCl (5 parts) and treated a for the coupling of CF CICFCII and CFCI CCI I described in the preceding example.

(1) Solvent (2) CF ClCFClCFClCF Cl4l% yield (cf. Example I) (3) CFCl CFClCFClCFCl 43% yield (cf. Example (4) 1,l,2,3,4-pentachloropentafluorobutane (CF ClCFClcFClCFCl 47% yield, B.P. 140--146 C./400 mm., 175

C./760 mm. (micro). (Found: Cl, 55.3; C Cl F requires Cl, 55.4%.)

DEHALOGENATION OF CFzClCFClCFClCFCla 4.9 parts of CF ClCFClCFClCPCl were dehalogenated as described for CF C1CFC1CCl CF Cl in Example VIII to give l-chloropentafluorobuta-1,3-diene (CF =CFCF=CFCl) in 78% yield. B.P. ca. 40 C. (micro).

(Found: Cl

Distillation gave:

(Found: C1,

19.9; M, 180. C C1F requires Cl, 19.9; M, 178.5.)

Example XI PREPARATION OF CFzClCHClI 500 parts of iodine monochloride and 300 parts of 'CF =CHCI were charged to a stainless steel cylinder which was shaken for 8 hours While being cooled. 'After 22 the 8 hour period, the contents were discharged, washed with 500 parts of a 15% sodium thiosulfate solution, dried and distilled to yield 680 parts of 1,2-dichloro-1,ldifiuoroiodoethane, CF CICHCII, B.P. 126 C.

COUPLING OF CFzClCHClI TO FORM CF2CICHCICHCICF2C1 Into a glass tube having a 15 watt germicidal fluorescent light mounted therein was charged 800 parts of CF ClCHClI and 3,090 parts of mercury. The glass tube was evacuated and then shaken, while being irradiated, for a period of 48 hours. The organic material was then separated from the mercury compounds by vacuum distillation and fractionated to produce a 50% yield of 1,2,3,4-tetrachloro-1,1,4,4-tetrafluorobutane,

CF ClCHClCHClCF C1 B.P. 1468 C.

DEHALOGENATION 0F CFaCHClCHClCFzCl 464 parts of CF CHClCHC1CF Cl were added dropwise to 190 part of zinc dust suspended in 240 parts of ethanol during the course of 3 hours while the ethanol was refluxed vigorously by heating. The addition was interrupted when about half completed and 50 parts of additional Zinc dust were added. The product was obtained as a gas by this treatment and was passed through an efiicient condenser, in the jacket of which water was circulating at a temperature of 35 C., thence through a tower packed with granular calcium chloride, and was condensed in atrap cooled in a salt-ice freezing mixture. parts of 1,1,4,4-tetrafiuorobuta-l,3-diene,

were obtained and parts of organic material were recovered from the ethanol by dilution with water.

Example XII PREPARATION OF CFa CH8) C: CFCF: CFz AND (CFa) 2C: CFCF: CF

The compound CF (CH )CHCFClI (l-chloro-l-fiuoro-1-diodo-2-trifluoromethylpropane) coupled with CF ClCFClI by the photochemical method (Hg and ultra-violet light) or by the preferential intermolecular deiodination method (Zinc' and dioxan), gave CF (CH )CHCFClCFClCF Cl (1,2,3-trichloro-1,1,2,3 tetrafluoro 4 trifluoromethylpentane). Treatment of the last compound with a conventional dehydrohalogenating agent, namely alcoholic potassium hydroxide, in turn gave (4,5-dichloro-3,4,5,5-tetrailuoro-2 trifluoromethylpent-Z- ene) and this compound with a dehalogenating agent, namely zinc and ethanol, yielded the desired diene CF CH C: CFCF=CF (l,l,2,3-tetrafluoro-4 trifluoromethyl penta 1,3 diene). (Found: C, 34.1; M, 208, C H F requires C, 34.6%; M, 208.)

(CF CHCFCII similarly yields (CF C=CFCF= CF (1,l,2,3,5,5,5 heptafluoro 4 trifluoromethylpenta- 1,3-diene) by coupling followed by dechlorination.

The starting compounds (CF (CHQCHCFCII and (CF CHCFCII employed above may be prepared, for example, by the interaction of CH CH=CFCI or CF CH=CFCl and trifiuoroiodomethane under conditions favoring a free radical reaction.

Example XIII COUPLING 0F IODO COMPOUNDS C1(CF2CFCI)nI (a) The compound Cl(CF CFC1) I, 5.1 parts, prepared as described in my copending application, Serial No. 526,086, filed August 2, 1955, was mixed with 7.8 parts of a CF ClCFC1 diluent and sealed in a silica tube with parts of mercury and shaken vigorously while exposed to ultra-violet light for a period of 8 days. The

23 organic material was extracted from the mercury iodides using ether and distillation of the extract produced the compound Cl(CF CFCl) (CFClCF Cl in a yield of 81%, B.P. 142144/20 mm., Hg absolute. (Found: C, 17.9; C1, 39.7. Required: C, 19.7; C1, 39.7), 11 1.408.

(b) 4.9 parts of the compound Cl(CF CFCl) I, prepared as described in my co-pending application, Serial No. 526,086, filed August 2, 1955, and treated as in (a) above, produced the compound Cl CF CFCI) 3 (CFClCF C1 in a yield of 74%, B.P. 195-200/ca. 10- mm., Hg absolute. (Found: C, 18.7; C1, 36.8. Required: C, 18.7; C1, 36.9.)

DECHLORINATION OF Cl(CF2CFCl)n(CFClCF )nCl POLYMERS (a) 6.7 parts of Cl(CF CFCl) (CFClCF Cl were diluted with 16 parts of ethanol and added dropwise to a mixture of zinc and refluxing ethanol. After a period of one hour the contents of the reaction flask were filtered and added to an excess of water. The lower layer was distilled from P to produce the compound CF =CFCF CF=CFCF CF=CF in a yield of 78%, B.P. 99100 C. (Found: C, 29.8; H, 0; F, 70.0; M, 325. Required: C, 29.6; H, 0; F, 70.4; M, 324), and an unidentified fraction of higher boiling point. The triene was reconverted into the parent chloro-compound by a photochemical reaction by a 100% excess of chlorine, showing that cyclization had not occurred, and that the triene was not contaminated by hydrogen containing compounds.

(b) The reaction in (a) above was repeated at a temperature of 50-55 C. during a period of hours. Only a trace, of the triene was formed and a different product, CF =CFCF CFClCFClCF CF=CF was obtained in a 51% yield, some of the parent hexachlorocompound remaining unchanged. The product had a boiling point of 58 C./20 mm., Hg absolute. (Found: C, 24.2; H, 0; Cl, 17.7. Required: C, 24.3; H, 0; Cl, 18.0.)

(c) 8 parts of the compound Cl(CF CFCl) 3 CFCICF Cl were treated as in (a) above to produce the compound CF =CFCF CFClCF CF=CFCF CFC1CF CF=CF in a yield of 65%, B.P. 115120 C./20= mm., Hg absolute. (Found: C, 25.6; H, 0; Cl, 12.6. Required: C, 25.8; H, 0; Cl, 12.8.) This triene absorbed 3 moles of chlorine when treated with an axcess thereof and exposed to ultra-violet light for a period of one day.

(d) Mild treatment of the compound Cl (CF CFCl) 3 (CFClCF C1 with zinc and ethanol as in (b) above produced the compound CF =CFCF CFCICF CFClCFClCF CFClCF CF=CF in a yield of 56%, B.P. 150-152 C./0.1 mm., Hg absolute. (Found: C, 22.8; H, 0; C1, 22.2. Required: C, 232.9; H, 0; Cl, 22.6.)

Example XIV OXIDATION OH on: CFCFzCF: CFCFzCF: CF,

The triene CF =CFCF CF=CFCF CF=CF was prepared by the reaction of CF CICFClI with chlorotrifluoroethylene to give CF ClCFClCF CFC1I. This last compound was then shaken with mercury and exposed to ultra-violet light to give the coupled product which on treatment with zinc and ethanol gave the desired triene.

5.7 parts of the triene thus prepared were oxidized, employing potassium permanganate in the presence of sodium bicarbonate as the oxidizing agent, following the general procedure described by Haszeldine in J.C.S. (1952), the reaction mixture being heated at a temperature of C.

for 1 hour and then at a temperature of 60 C. for 1 hour. The product was worked up with S0 sulphuric acid and ether extraction and an ethereal solution of perfluoromalonic acid, CF (CO H) was obtained. Evaporation of the ethereal solution gave CF (CO H) (Found: C, 25.7%; equiv., 70. Required: C, 25.7%; equiv. 70), as a solid which after distillation at 10- mm. and recrystallization from benzene had a melting point of 118 C. (Yield, 63%.) Henne and Dewitt (JACS 70, 1548, 1948), reported that difluoromalonic acid was readily decarboxylated to difiuoroacetic acid and failed to isolate the free acid. Under the conditions just described, decarboxylation does not occur and the acid is quite stable. It can, in fact, be heated to 160 C. without decarboxylation. Treatment of an ethereal solution of perfluoromnlonic acid with diazomethane according to the procedure described by Henne and Dewitt gave the compound CF (CO CH (81% yield) having a boiling point of 60 to 62 C./12 mm. Hg absolute. (Found: C, 35.6%; H, 3.5%. Required: C, 35.7% H, 3.6%.) No methyl difluoroacetate was formed. For final identification of the compound, an ethereal solution of the dimethyl ester was converted into the amide CF (CONH having a melting point of 207 C. Found: C, 26.0%; H, 2.8%; N, 20.3%. Required: C, 26.1%; H, 2.9%; N, 20.3%.) The infra-red spectrum of this amide was identical with that of the amide prepared by an alternative route.

Example XV OXIDATION OF CF2:CFCF CFClCFClCF2CF=CFa 6.7 parts of the diene (prepared as described in Example XIII) were oxidized, using potassium permanganate as the oxidizing agent, as described in Example XIV above, to produce a 51% yield of the compound HO CCF CFClCFClCF CO H, which was obtained as a waxy solid upon evaporation of the ethereal solution. The compound was analyzed without further purification. (Found: C, 22.6%; H, 0.6%; Cl, 22.2%; equiv., 161.5. Required: C, 22.3%; H, 0.6%; Cl, 22.0%; equiv., 162.5.)

0.8 part of the dicarboxylic acid was then converted into the dimethylester by treatment with diazornethane. The dimethylester had a boiling point of 155 to 158 C./2 to 4 mm. Hg absolute. (Found: C, 27.4%; H, 1.6%; Cl, 20.0%. Required: C, 27.4%; H, 1.7%; Cl, 20.2%.)

The remainder of the dicarboxylic acid was divided equally one portion being converted into the silver salt and the other into the sodium salt, each of which was thoroughly dried.

One gram of the disilver salt of the dicanboxylic acid was converted into the compound CF CICFCICFClCF Cl by reaction thereof with a stoichiometric excess of chlorine at a temperature of C. in a sealed tube. The yield was 69%. Treatment of this product with zinc and refluxing ethanol converted the chloro compound into hexafluorobutadiene.

2.1 parts of the disodium salt of the dicarboxylic acid (found: Na, 12.5%. Required: Na, 12.7%), were powdered and pyrolysed in vacuo in a platinum tube at initial temperature of C., which rose to 420 C. at the end of the pyrolysis. The products, condensed by liquid oxygen, were washed with a solution of sodium hydroxide having a concentration of 5% by weight and distilled in vacuo to provide a 71% yield of hexafluorobutadiene, which was identified by means of its infra-red spectrum.

Example XVI COUPLING C4FOCF(CF3) [CHzCHz] 111 The compound C4F9CF [CH2CF2]3 5 l was 25 prepared as described in Patent No. 2,975,220 of Hauptschein and Braid.

Eight milliliters of mercury, 12.5 g. (0.019 mole) of [CH2CF2]3'5 l, and Of 1,1,2-t1'l chlorotrifluoroethane in a Vycor tube were shaken and exposed to ultraviolet irradiation for five days. The coupled product (C F CF(CF [CH CF 0 was an oil, B.P., 170230 C. at ca. 0.1 mm.; viscosities: 318 cs. at 784 F., 58.7 cs. at 123.8 E, cs. at 197.8 F.; ASTM slope (78198 'F.), 0.87. The conversion and yield were 83%.

By the same procedure, 14 g. (0.018 mole) of and 8 ml. of mercury, in 10 ml. of 1,1,2-trichlorotrifiuoroethane were shaken and exposed to ultraviolet light for five days. The coupled product B.P. ISO-260 C. at ca. 0.4 mm., was an oil, partially solid at 25 C., viscosities; 520 cs. at 100 F. (extrapolated), 204 cs. at l23.8 R, 26.5 cs. at 197.8 F., 21.8 cs. at 210 F. (extrapolated); AS'IM slope (124- 198" F.), 0.77. The conversion and yield were 85%.

Example XVII v COUPLING CFaCF CFaCl) [CHzCFz] nI The compound CF CF(CF Cl) [CH CF ,,.,;I was prepared as described in Patent No. 2,975,220 referred to above.

Twenty grams (0.036 mole) of 8 ml. of mercury, and 10 ml. of 1,1,2-trichlorotrifiuoroethane were shaken in a Vycor tube under ultraviolet light for 4 days. The coupling product,

B.P. l53240 C. at ca. 0.1 mm., was a heavy oil; viscosities: 455 cs. at 78.4 F., 181 cs. at 100 F. (extrapolated), 86.4 cs. at l23.8 F., 14.6 cs. at 197.8 F.,

11.95 cs. at 210 F. (extrapolated); ASTM slope (78- 198" F.), 0.79. The yield and conversion were 83%.

Twenty two grams (0.035 mole) of 8 ml. of mercury, and 10 ml. of 1,1,2-trichlorotrifluoroethane in a Vycor tube were exposed to ultravoilet irradiation while shaking for 6 days. The main fraction of coupled product,

B.P., 153-2l0 C. at 0.1 mm. was a heavy oil partially solid at 25 C., viscosities: 249 cs. at 123.8 F., 610 cs. at 100 F. (extrapolated), 34.6 cs. at 197.8 F., 28 cs. at 210 F. (extrapolated); ASTM slope (124-l98 F.), 0.71. The yield and conversion were 70%.

Example XVIII COUPLING 0FVCF8[CH2CF2]11I Sixteen grams (0.062 mole) of CF CH CF I and 8 ml. of clean dry mercury were sealed under a dry nitrogen atmosphere in a 50 ml. Vycor tube. After shaking for several days under ultraviolet irradiation, the tube was opened; l,1,2-trichlorotrifluoroethane was added, and the reaction mixture was filtered to remove mercury and solids. Several additional portions of solvent were used to wash the residue on the filter, and all the filtrates were combined. After removal of the solvent by distillation, the coupled product, CF CH CF CF CH CF was obtained as a colorless oil, B.P. 83 at 760 mm.

Analysis.Calcd. for C H F C, 27.1; H, 1.5; F, 71.4. Found: C, 27.2; H, 1.97; F, 71.0. The yield and conversion were 49%.

By the above procedure, 18 g. (0.056 mole) of CF [CH CF I and 8 ml. of mercury were shaken and irradiated with ultraviolet light for two days. The tube was opened, and, after the addition of 10 ml. of 1,1,2- trichlorotrifluoroethane, rescaled and irradiated with shaking for several additional days. The coupled product, (CF3[CH2CF2]2)2, a Whltfi solid, 3840 was isolated by distillation, B.P., at 25 mm.

Analysis-Calcd. for C H F C, 30.5; H, 2.1; F, 67.5. Found: C, 30.5; H, 2.4; F, 67.2. The yield and conversion were 54%.

Similarly, thirteen grams (0.034 mole) of and 6 ml. of mercury were irradiated for two days. The tube was opened, 10 ml. of 1,1,2-trichlorotrifluoroethane were added, and tube was rescaled and returned to the shaker for several additional days. The coupling product, (CF [CH CF isolated by sublimation was a white solid, MP. 4044".

Analysis.Calcd. for C H F C, 32.2; H, 2.3; F, 65.5. Found: C, 31.9; H, 2.4; F, 65.3. The yield and conversion based on the product isolated were 29%; however, in this case as well as in the two previous runs, efforts to separate all the product were not made. The actual conversions are estimated to be of the order of 80%.

Example XIX COUPLING OF CFzClCFClIfCHzCFflJ By-use of the procedure described in Example XVIII 10 g. (0.024 mole) of CF ClCFCl[CI-I CF W I were converted to the coupling product,

(CF ClCFCl 2 2] 2.2 av. 2

an oil, B.P. -165 at ca. 0.1 mm., viscosity 15.3 cs. at 123.8 F., in 61% conversion and yield after shaking in a Vycor tube with 9 ml. of mercury and 10 ml. of 1,1,2-t1ichlorotrifiuoroethane under ultraviolet irradiation for 4 days.

Similarly, 10 g. (0.019 mole) of CF ClCFO1[CH CF av, I

9 m1. of mercury and 10 ml. of 1,1,2-trichlorotrifluor-oethane were shaken in a Vycor tube for 4 days while exposed to ultraviolet light. The coupling product,

(CF ClCFCl [CH CF 4 I 2 was isolated as the fraction boiling mainly at 215-225 at ca. 0.1 mm., solid at room temperature. The yield and conversion were 54%.

Example XX COUPLING OF CFsCFeCFzI l-iodoperfluoropropane (29.6 g., 0.1 mole) and 10 ml. of mercury were sealed in a Vycor 7900 tube under a dry nitrogen atmosphere and shaken end to end for 9 days while exposed to ultraviolet irradiation. The en tire product was finally converted to a brown solid mass. 1,1,2-trichloro-1,2,2-trifluoroethane was then added to the opened tube, which was resealed and irradiated for an additional 3 days When the solids were completely black. The cooled tube was then opened, the volatile contents were transferred in vacuo to a Vigreux unit and distilled. There were collected 33 g. of distillate, B.P. 42-44 C., n 1.30. This material was analyzed spectroscopically and found to be a 50:50 n-C F CF ClCFCl mixture (probably an azeotrope). Thus the yield of n-perfluorohexane was 16.5 g. or 98%.

Example XXI COUPLING OF CF ClCFClCFhCFClI WITH ZINC AND ACETIC ANHYDRIDE-METHYLENE CHLORIDE Eighty ml. of acetic anhydride, 80 ml. of methylene chloride, 6.5 g. (0.10 g. atom) of 30 mesh granular activated Zinc and 39.5 g. (0.1 mole) of CF CICFCICF CFCII were allowed to react for about hours at -32" C. There was isolated 22.3 g. (83%) of B.P. 140-147 C. mm).

As illustrative of certain new chemical compounds that have been prepared as starting materials for use in the coupling reaction of the invention, may be mentioned the following:

CF BrCFClI CF CICCI I CF BrCCl I CFCl CCl l CFCI CFCII OFQ CHCFClI CHCFClI The coupling reaction of the invention, when carried out with mercury, has also produced classes of mercurycontaining chemical compounds, namely in which R, X, Y and Z have the meanings ascribed in the early part of this specification. Illustrative of these new compounds is the mercury compound:

The compounds which have been described have a variety of uses. Those compounds which are gaseous can be employed, for example, as dielectrics, refrigerants, sealing liquids in gas trap where corrosive gases ahe handled, fire extinguishers, propellants and aerosols. Those compounds which are liquids may be used as dielectrics, heat transfer media in situations Where resistance to thermal and chemical degradation is important, as solvents for fiuorogreases, as media for the preparation of dispersions of fiuoropolyenes such as Teflon and Kel-F, as instrument liquids in float instruments and manometers, as extractants, and as plasticizers. Where the liquids are oily or greasy in nature they are lubricants of choice in applications where high thermal and chemical stability are required. Certain of the liquid products, for example the -SO H and -COOH acids described above have surface active properties. The SO H acids are used for example in chromium plating baths where in concentration of less than 1% they prevent losses of valuable metals.

When the compounds are solids they may be used in gaskets or valve packings, particularly when corrosive fluids are to be hand-led, as coatings for use in machinery Where chemical protection is required without toxicity, e.g. in bread making machinery; and in insulating and packing materials.

This wide range of utilities can be illustrated by a few specific cases.

The compound, (CF CHCF CD [CH CF CF II obtained in Example VXII is characterized by remarkably good viscosity-temperature characteristics. Fluorocarbon oils are well known to be useful as heat resistant lubricants, because they will not decompose at elevated temperatures. One drawback to their use has been, however, that their viscosity decreases sharply with increasing temperature. The above coupled product shows great improvement over other fluorocarbon oils in this respect.

The compound HOOCCF CFClCFClCF COOH obtained in Example XV shows good surface active properties. In a concentration of less than 0.3% it reduces the surface tension of water to less than 30 dynes/ cm. It is especially useful in the persulphate polymerization of chlorotrifluoroethylene where it increases the molecular weight of the product substantially.

The compound, Cl(CF CFCl) (CFClCF Cl, obtained in Example XIII is an oil which can be used to lubricate apparatus operating in corrosive atmospheres, such for example as laboratory motors and steering apparatus operating in atmospheres of HF and F While such atmospheres would cause hydrocarbon oils to thicken or even catch fire after a short time, oils of the above type Will perform for weeks without replacement.

The compound hexafiuoro-1,3-d-iene whose preparation via a coupling reaction is described in Example I above is a valuable monomer. It can be formed into valuable polymeric products using the general technique described in the Hauptschein et al. article referred to above.

Other uses to which the compounds of the present invention may be put will be apparent to those skilled in the art.

What is claimed is:

1. A method for making compounds having the general formula RCXYCXY R which comprises coupling two molecules having the formula RCXY Z where R is selected from the group consisting of alkyl and halogenoalkyl groups having from 1 to about 20 carbon atoms, Z is selected from the group consisting of bromine andiodine, Y is a halogen atom of no greater atomic weight than Z and X is selected from the group consisting of hydrogen and halogen atoms having no greater atomic weight than Z.

r 29 2. A method of making compounds having the general formula f( j)p( m) q f where R; and R f are selected from the class consisting of fluoroalkyl, fluorochloroalkyl, and fluorobromoalkyl groups having from 1 to about 20 carbon atoms, where R, and R are fluoroalkylene groups, the carbon atom in (R,),, nearest to (R,,,).,- and the carbon atom in -(R nearest to --(R each having one substituent selected from the group consisting of hydrogen, fluorine, chlorine and bromine, and one substituent selected from the group consisting of fluorine, chlorine and bromine and where p and q are numbers from 1 to about 20, which comprises coupling two molecules having the formula r( j)p and v m)q 'r where Z is selected from the group consisting of bromine and iodine.

3. A- method of coupling halogenated organic compounds having the general formula RCXY Z where Z is selected from the class consisting of bromine and iodine, Y is a halogen atom of no greater atomic weight than Z, X is selected from the class consisting of hydrogen and halogen atoms having no greater atomic weight than Z and R is selected from the class consisting of alkyl, and halogenoalkyl groups having from 1 to about 20 carbon atoms which comprises subjecting such compounds to energization suflicient to cause fission of the C-Z bond in the above formula.

4. The method claimed in claim 3 in which the compounds are subjected to energization in the presence of a halogen acceptor.

5. The method claimed in claim 3 wherein the energization is conducted by means of ultra-violet radiation.

6. The method claimed in claim 3, wherein the reaction is conducted by means of ultra-violet light in the presence of mercury.

7. The method claimed in claim 3 wherein the reaction is conducted by heating said compounds.

f 8. A method of coupling halogenated organic compounds having the general formula RCXY Z where Z is selected from the class consisting of bromine and iodine, Y is a halogen atom of no greater atomic weightthan Z, X is selected from the class consisting of hydrogen and halogen atoms having no greater atomic weight than Z and R is selected from the class consisting of alkyl and halogenoalkyl groups having from 1 to about 20 carbon atoms, which comprises reacting said compound w-ith a dehalogena-ting metal in the presence of an organic solvent, having a dielectric constant greater than 1.5.

9. The method claimed in claim 8 wherein the solvent is a Lewis base.

10. The method claimed in claim 8 wherein the metal is selected from the group consisting of zinc, magnesium, tin, iron, aluminum, copper and cadmium.

11. A method of making compounds having the general formula in which X" and Q are selected from the group consisting of chlorine and bromine, Y" and U are selected from the group consisting of chlorine and fluorine, R and R are fluoroalkylene groups, the carbon atom in -(R nearest to (R,,,),,- and the carbon atom in ---(R,,,),,--- nearest to (R each having one substituent selected consisting of fluorine, chlorine and bromine, and where p and q-are members from 1 to about 20 which comprises coupling two molecules of the structure CF XCClY"(R Z and CF QCClYU(R Z where Z and Z are selected from the group consisting of bromine and iodine.

12. A method of making compounds of the formula CFgX 'CClY CF CFCl p (CF ClCF CCIUCF Q where X and Q are selected from the group consisting of chlorine and bromine, where Y and U are selected from the group consisting of fluorine and chlorine and where p and q are numbers from 1 to about 20 which comprises coupling two compounds having the formula CF XCClY(CF CFCl) Z and CF QCCIU CF CFCI) Z bromine and iodine.

from the group consisting of hydrogen, fluorine, chlorine 13. A method of making compounds having the formula R [CH CF [CF CH ]R where R; is selected from the class consisting of fluoroalkyl and fiuorochloroalkyl groups having from 1 to say 20 carbon atoms, and n is from 1 to about 20 which comprises coupling two molecules having the formula where Z is selected from the group consisting of bromine and iodine.

14. A method of making compounds of the formula where R is a perfluoroalkyl group having from 1 to about 20 carbon atoms and n is from 1 to about 20, which comprises coupling compounds of the formula where Z is selected from' the group consisting of bromine and iodine.

15. A method of making compounds of the formula where R" is a perfluorochloroalkyl group having from 1 to about 20 carbon atoms and n is from 1 to about 20, which comprises coupling compounds of the type where Z is selected from the group consisting of bromine and iodine.

16. A method for making hexafluoro-l,3-diene which comprises coupling a compound having the formula CF YCF ClI Where Y is selected from the group consisting of chlorine and bromine, to give the coupled product and dehalogenating the coupled product.

17. A method of making compounds of the general class R R R C-C X' 'Y' n CXY'CR R R where R is selected from the group consisting of perfluoroalkyl, perfluorochloroalkyl and perfluorobromoalkyl groups having 1 to 20 carbon atoms, R and R are selected from the group consisting of hydrogen, halogen and halogenoalkyl having from 1 to 10 carbon atoms and n is not greater than 20, which comprises reacting two molecules having the general formula 31 where Z is selected from the group consisting of bromine and iodine, in the presence of molecular oxygen.

18. A method for making compounds of the structure RC'X"=CXR where R is selected from the group consisting of alkyl and halogenoalkyl groups having from 1 to about 20 carbon atoms, and X is selected from the group consisting of hydrogen, fluorine, chlorine and bromine which comprises coupling two molecules RCX'X Z where X" is selected from the group consisting of chlorine and bromine, Z is selected from the group consisting of bromine and iodine, and X is selected from the group consisting of hydrogen, chlorine and bromine to form a coupled product RCXX"CXX*-R and removing the X" substituent from the C carbon atom and X substituent from the C carbon atom. 19. A method of making compounds of the type CX '=CX-CX=CX where X is selected from the group consisting of hydrogen, fluorine, chlorine and bromine which comprises 7 coupling two compounds having the structure CX X-CXX"Z and CX' X"CX'X"Z where X is selected from the group consisting of chlorine and bromine and Z is selected from the group consisting of bromine and iodine to form the coupled product CXIZXI CIXIXI ICXIXI CXI IX!2 and dehalogenating said coupled product.

20. A method of making compounds of the type where X is selected from the group consisting of hydrogen, fluorine, chlorine and bromine and where R, and R are selected from the class consisting of alkyl and halogenoalkyl groups, having from 1 to about 20 carbon atoms, which comprises coupling two molecules having the structure where Y is selected from th egroup consisting of fluorine, chlorine and bromine, X is selected from the group consisting of hydrogen, chlorine and bromine and Z is selected from the group consisting of bromine and iodine, but is of no less atomic weight than any other halogen in the molecule, provided that at least one of X and Y' is capable of forming with X a molecule selected from the group consisting of HBr, HCl, Br and C1 to form the coupled product OIXBOQX'YCQX'YC1XR/ R RB and removing the X substituents from the C carbon atoms and one of the X and Y' substituents from each of the C carbon atoms in said coupled product.

21. A method for making branched chain dienes of the type 32 where R and R are selected from the group consisting of alkyl and halogenoalkyl groups having not more than about 17 carbon atoms and X is selected from the group consisting of hydrogen, fluorine, chlorine and bromine, which comprises coupling a compound of the type CXCXYZ where Y is selected from the group consisting of fluorine, chlorine and bromine and Z is selected from the group consisting of bromine and iodine and has an atomic weight at least as great as any other halogen in the compound, with a compound of the type CX YCXYZ to give a coupled product of the formula CXCXYCXYCXZY' e and removing two atoms of X and two atoms of Y' from each molecule of said coupled product.

22. A method of making compounds of the structure 0 0YCX'Y (CX2 n1OX=CX 2 e where R and R are selected from the class consisting of alkyl and halogenoalkyl groups having from 1 to about 20 carbon atoms, Y is selected from the group consisting of fluorine, chlorine and bromine, X is selected from the group consisting of hydrogen, fluorine, chlorine and bromine and n is a number from 1 to about 20, which comprises coupling two molecules having the structure CX"'CX YZ and CX3(CX;) n--CXYZ e where X and X are selected from the group consisting of hydrogen, chlorine and bromine, but are not both hydrogen, where at least one of the X atoms attached to the C carbon atom is selected from the group consisting of hydrogen, chlorine and bromine, and where at least one ofthe X atoms on the carbon atom adjacent the C carbon atom is capable of forming with said one atom on the 0 carbon atom, a compound selected from the class consisting of HCl, HBr, C1 and Br Z being selected from the group consisting of bromine and iodine and having at least as great an atomic Weight as any other halogen in the molecule, to form a coupled product of the structure Rt\ I CXCX Y CX Y -(CX Z)n'OX3 R2 and removing the X and X carbon atoms, said one X atom from said C carbon atom and said one X atom from said carbon atom adjacent said O carbon atom. 23. A method of making compounds of the type CX' =CX(CX' CX'Y- CXY(CX' CX"=CX where X is selected from the group consisting of hydrogen, fluorine, chlorine and bromine, Y is selected from the group consisting of fluorine, chlorine and bromine and n is from 1 to about 20 which comprises coupling two molecules having the structure CX (CX -CXYZ and CX' (CX' --CXYZ where Z is selected from the group consisting of bromine and iodine and has at least as great an atomic weight as any other halogen in the molecule, X, Y and n are as defined; provided that at least one X substituent on each of the C' and C carbon atoms is of the class consisting of hydrogen, chlorine and bromine and that at least one substituent on the carbon atoms adjacent the C and C carbon atoms is such as to be capable of forming with said one substituent on the C and C carbon atoms a molecule of the class consisting of C1 Br HCl and HBr, to form a coupled product of the structure CX (CX' CXY'CX'Y-(CX CX' and removing one X atom from each of said C and C carbon atoms and from each of the carbon atoms adjacent thereto.

24. A method of making compounds of the structure where U and Y are selected from the group consisting of chlorine and fluorine, R and R are fluoroalkene groups, the group (R having on the carbon atom nearest the (R,,,),, group at least one atom selected from the group consisting of hydrogen, fluorine, chlorine and bromine and at least one atom selected from the group consisting of fluorine, chlorine and bromine, and where p and q are from- 1 to about 20 which comprises coupling two molecules of the structure where Q and X" are selected from the group consisting of bromine and chlorine and Z and Z are selected from the group consisting of bromine and iodine to form the coupled product and dehalogenating said product.

25. A method for making compounds of the formula.

where n is from to about 20, which comprises coupling compounds of the type Where X" is selected from the group consisting of chlorine and bromine and Z is selected from the group consisting of bromine and iodine and has anatomic weight at least as great as any other halogen in the molecule, to give a coupled product of the type and dehalogenating said coupled product to remove all the X" atoms therefrom.

26. A method for making compounds of the type C X C X (CX' CX= C X' (CX C X"=C X where X is selectedfrom the group consisting of hydrogen, fluorine, chlorine and bromine and n is from 0 to about 20 which comprises coupling two compounds of the type C X 2X C X X (CX' C XY'Z where Z is selected from the group consisting of bromide and iodine and has at least as great an atomic weight as any other halogen in the formulae, where X, X, X and X are selected from the group consisting of hydrogen, chlorine and bromine and not more than one of X and X and of X and X are hydrogen; where Y is selected from the group consisting of fluorine, chlorine and bromine, provided that at least one of the X and Y substituents on each of the C and C carbon atoms is selected from the group consisting of hydrogen, bromine and chlorine and that when the X substituent on said C carbon atom is hydrogen said C carbon atom has a sub- 34 stituent selected from the group consisting of chlorine and bromine, to form a coupled product, having the structure (CX ),,C XXC X X' and removing a molecule selected from the class consisting of HBr, HCl, Br and C1 from each of the following pairs of'carbon atoms: C and C C and C C and C 27. A method for making fluorinated trienes which comprises coupling -two compounds of the formula CF X"CClY(R (R -CX'X)Z and CF QCC1U (R (R CX'Q) Z where X" and Q are selected from the group consisting of chlorine and bromine, Y" and Q are selected from the group consisting of fluorine and chlorine, Z and Z are selected from the group consisting of bromine and iodine, X is selected from the group consisting of hydrogen, fluorine, chlorine and bromine, p and q are from 1 to 20, Rj and R are fluoroalkylene radicals having on their terminal carbon atoms nearest the Z atoms, one atom of the class consisting of chlorine and bromine and one atom of the class consisting of hydrogen, fluorine, chlorine and bromine, and R and R are R, and R respectively, less their terminal carbon atoms, to form the coupled product as great as any other halogen in the molecule to give the coupled product and dehalogenating said coupled product to remove the X component therefrom.

29. A method of making dicarboxylic acids of the general formula where R, and R are fluoroalkylene radicals Where the group -(R has on the carbon. atom nearest the group (R,,,),, and the group (R,,,),,- has on the carbon atom nearest the group (R:),, at least one atom of the group consisting of hydrogen, fluorine, chlorine and bromine and at least one atom of the group consisting of fluorine, chlorine and bromine and where p and q are from 1 to about 20 which comprises coupling two compounds of the type Where X" and Q are selected from the group consisting of chlorine and bromine, where Y and U are selected from the group consisting of fluorine and chlorine and where Z is selected from the group consisting of bromine and iodine, to form the coupled product a dehalogenating said coupled product to give the compound CF =CCl(R,-) (R Cl=CF and oxidizing the last named compound.

30. A method for making fluorin-ated carboxylic acids which comprises oxidizing a triene of the formula Where Y and U are selected from the group consisting of fluorine and chlorine, p and q are numbers from 1 to 20, R, and R are fluoroalkylene groups having on their terminal carbon atoms nearest the R and R groups, respectively, at least one atom selected from the group consisting of hydrogen, chlorine and bromine and at least one atom selected from the group consisting of chlorine and bromine, where R and R, are R, and R respectively, less their terminal carbon atoms, to give acids having the formulae 31. A method of making a sulphonic acid compound of the general formula where U and Y are selected from the group consisting of chlorine and fluorine, R and R are fluoroalkylene groups, the group (R,-),, having on the carbon atom nearest the -(R,,,),, group and the (R,,,),, group having on the carbon atom nearest the -(R group at least one atom selected from the group consisting of hydrogen, fluorine, chlorine and bromine and at least one atom selected from the group consisting of fluorine, chlorine and bromine, and where p and q are from 1 to about 20, M being an alkali metal, which comprises reacting a salt, MHSO with a compound 36 References Cited in the file of this patent UNITED STATES PATENTS 2,174,506 Fox Sept. 26, 1939 2,181,890 Harris Dec. 5, 1939 2,392,316 Dreyfus Jan. 8, 1946 2,404,374 Harmon July 23, 1946 2,407,246 Benning et al. Sept. 10, 1946 2,432,997 Ligett et a1. Dec. 23, 1947 2,450,858 Fitzpatrick et al. Oct. 5, 1948 2,490,764 Benning et a1 Dec. 13, 1949 2,504,034 Morrell et al. Apr. 11, 1950 2,554,857 Gochenour May 29, 1951 2,649,477 Jacobs et a1 Aug. 18, 1953 2,668,182 Miller Feb. 2, 1954 2,670,387 Gottlieb et a1. Feb. 23, 1954 2,676,193 Ruh Apr. 20, 1954 2,705,229 Ruh et a1 Mar. 29, 1955 2,716,141 Miller Aug. 23, 1955 2,732,398 Brice et al. Jan. 24, 1956 2,771,487 Morris et a1. Nov. 20, 1956 2,784,221 Bordenca Mar. 5, 1957 2,824,891 Polliltzer Feb. 25, 1958 2,833,831 Haszeldine May 6, 1958 2,852,565 Nozaki Sept. 16, 1958 OTHER REFERENCES Fieser et al.: Organic Chemistry, 1944, pages 38 and 39, Heath and Co., Boston.

Henne et al.: Journal of the American Chemical Society, volume 67 (1945), pp. 1906-8.

Henne et al.: Journal of the American Chemical Society, volume 72 (1950), pp. 3577-9.

Fuson: Advanced Organic Chemistry, 1950, pp. 133 and 134, John Wiley & Sons, Inc., New York.

Haszeldine: Jour. Chem. Soc. (1952), pp. 4423-4431.

Haszeldine: Jour. Chem. Soc. (1952), pp. 2504-13.

Haszeldine et al.: Jour. Chem. Soc., May 1953, pp. 1592-1600.

Henne: Jour. Amer. Chem. Soc., 75, 5750, Nov. 20, 1953.

Henne et al.: Jour. Amer. Chem. Soc., 77, 2334-2335, April 20, 1955.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,046,304 July 24, 1962 Robert Neville Haszeldine It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 48, for "RCHXCX' X" R" read RCH XCX' X" R column 11, lines 52 to 57, the equation should appear as shown below instead of as in the patent:

intramolecular dehalogenation XI XI I I I! CF -CY (R R -CCR (R CU-CF column 13, line 58, for "CF =CF(CF CFCl) CF CF" read CF =CF(CF CFCl) CF CF column 16, line 32, for "1.4449 read 1.449 column 22, line 40, for "diodo"' read -iodo column 23, line 5, for "19.7" read 17.9 line 48, for "axcess" read excess line 58, for "232.9" read 22.9 same column 23, line 74, after "J.C.S." insert 4259 column 28, line 28, for "VXII" read XVII column 33, line 55, the equation should appear as shown below instead of as in the patent:

Signed and sealed this 5th day of March 1963.

(SEAL) Attest:

ESTON G. JOHNSON DAVID L. LADD Attestinq Officer mm".- --1 I r 

1. A METHOD FOR MAKING COMPOUNDS HAVING THE GENERAL FORMULA
 31. A METHOD OF MAKING A SULPHONIC ACID COMPOUND OF THE GENERAL FORMULA 